Effect of Extract and Fucoidan of Sargassum sp. on Growth, biochemical, Immunity and antioxidant Parameters of Nile Tilapia (Oreochromis niloticus)

Algae and seaweeds and their metabolites have been considered as promising alternatives in improvement of fish immune system and growth. The effects of extract and fucoidan extracted from Sargassum sp. was investigated in Nile tilapia with an average weight of 25 ± 5 for 60 days. The experimental groups included 0.5%, 1% and 2% of extract, and 0.5%, 1% and 2% of fucoidan. A group fed with basal diet was considered as control. In order to investigate the growth and immunity parameters, sampling was carried out on days 30th and 60th of the experiment. The results of this study showed that fucoidan and extract from Sargassum had no significant effects on gained weight, specific growth rate and feed conversion ratio after 60 days feeding (P>0.05). The amount of lysozyme as an important immunity parameter also did not significantly differ between the sampling times among the treatments (P>0.05). Also, there was no significant difference in serum total protein, albumin, globulin, cholesterol, triglyceride, alkaline phosphatase, alanine aminotransferase and aspartate aminotransferase levels among the groups after 30 and 60 days of experiment (P>0.05). Besides, the results of antioxidant parameters including superoxide dismutase, peroxidase and catalase enzymes did not show significant differences among the experimental groups at days 30 and 60 (P>0.05). Although inclusion of Sargassum did not have negative effect on growth rate of tilapia, it did not improve immunity of tilapia. Therefore, it is recommended to examine a wider range of concentrations of extract and fucoidan in future studies.